Basic hit testing functionality

8 files changed, 148 insertions, 20 deletions

diff --git a/src/components/gfx/display_list.rs b/src/components/gfx/display_list.rs
index 74c3bc0b45a..8a7d5135242 100644
--- a/src/components/gfx/display_list.rs
+++ b/src/components/gfx/display_list.rs
@@ -28,7 +28,7 @@ use std::arc;
 
 /// A list of rendering operations to be performed.
 pub struct DisplayList<E> {
-    priv list: ~[DisplayItem<E>]
+    list: ~[DisplayItem<E>]
 }
 
 impl<E> DisplayList<E> {
diff --git a/src/components/main/compositing/mod.rs b/src/components/main/compositing/mod.rs
index 63e4e55564b..c0b08be2f15 100644
--- a/src/components/main/compositing/mod.rs
+++ b/src/components/main/compositing/mod.rs
@@ -4,8 +4,9 @@
 
 use compositing::resize_rate_limiter::ResizeRateLimiter;
 use platform::{Application, Window};
-use script::script_task::{LoadMsg, ScriptMsg};
+use script::script_task::{LoadMsg, ScriptMsg, SendEventMsg};
 use windowing::{ApplicationMethods, WindowMethods};
+use script::dom::event::ClickEvent;
 
 use azure::azure_hl::{DataSourceSurface, DrawTarget, SourceSurfaceMethods};
 use core::cell::Cell;
@@ -222,10 +223,22 @@ fn run_main_loop(port: Port<Msg>,
         resize_rate_limiter.window_resized(width, height)
     }
 
+    let script_chan_clone = script_chan.clone();
+
     // When the user enters a new URL, load it.
     do window.set_load_url_callback |url_string| {
         debug!("osmain: loading URL `%s`", url_string);
-        script_chan.send(LoadMsg(url::make_url(url_string.to_str(), None)))
+        script_chan_clone.send(LoadMsg(url::make_url(url_string.to_str(), None)))
+    }
+
+    let script_chan_clone = script_chan.clone();
+
+    // When the user clicks, perform hit testing
+    do window.set_click_callback |layer_click_point| {
+        let world_click_point = layer_click_point + *world_offset;
+        debug!("osmain: clicked at %?", world_click_point);
+
+        script_chan_clone.send(SendEventMsg(ClickEvent(world_click_point)));
     }
 
     // When the user scrolls, move the layer around.
diff --git a/src/components/main/layout/layout_task.rs b/src/components/main/layout/layout_task.rs
index a45d46e6df8..7034593fbe2 100644
--- a/src/components/main/layout/layout_task.rs
+++ b/src/components/main/layout/layout_task.rs
@@ -8,6 +8,7 @@
 use css::matching::MatchMethods;
 use css::select::new_css_select_ctx;
 use layout::aux::{LayoutData, LayoutAuxMethods};
+use layout::box::RenderBox;
 use layout::box_builder::LayoutTreeBuilder;
 use layout::context::LayoutContext;
 use layout::display_list_builder::{DisplayListBuilder, FlowDisplayListBuilderMethods};
@@ -32,15 +33,17 @@ use newcss::types::OriginAuthor;
 use script::dom::event::ReflowEvent;
 use script::dom::node::{AbstractNode, LayoutView};
 use script::layout_interface::{AddStylesheetMsg, BuildData, BuildMsg, ContentBoxQuery};
-use script::layout_interface::{ContentBoxResponse, ContentBoxesQuery, ContentBoxesResponse};
-use script::layout_interface::{ExitMsg, LayoutQuery, LayoutResponse, LayoutTask};
-use script::layout_interface::{MatchSelectorsDamage, Msg, NoDamage, QueryMsg, ReflowDamage};
+use script::layout_interface::{HitTestQuery, ContentBoxResponse, HitTestResponse};
+use script::layout_interface::{ContentBoxesQuery, ContentBoxesResponse, ExitMsg, LayoutQuery};
+use script::layout_interface::{LayoutResponse, LayoutTask, MatchSelectorsDamage, Msg, NoDamage};
+use script::layout_interface::{QueryMsg, ReflowDamage};
 use script::script_task::{ScriptMsg, SendEventMsg};
 use servo_net::image_cache_task::{ImageCacheTask, ImageResponseMsg};
 use servo_net::local_image_cache::LocalImageCache;
 use servo_util::tree::{TreeNodeRef, TreeUtils};
 use servo_util::time::{ProfilerChan, profile, time};
 use servo_util::time;
+use std::net::url::Url;
 
 pub fn create_layout_task(render_task: RenderTask,
                           img_cache_task: ImageCacheTask,
@@ -67,6 +70,8 @@ struct Layout {
     local_image_cache: @mut LocalImageCache,
     from_script: Port<Msg>,
     font_ctx: @mut FontContext,
+    doc_url: Option<Url>,
+    screen_size: Option<Size2D<Au>>,
 
     /// This is used to root reader data.
     layout_refs: ~[@mut LayoutData],
@@ -90,6 +95,9 @@ impl Layout {
             local_image_cache: @mut LocalImageCache(image_cache_task),
             from_script: from_script,
             font_ctx: fctx,
+            doc_url: None,
+            screen_size: None,
+            
             layout_refs: ~[],
             css_select_ctx: @mut new_css_select_ctx(),
             profiler_chan: profiler_chan,
@@ -102,6 +110,21 @@ impl Layout {
         }
     }
 
+    // Create a layout context for use in building display lists, hit testing, &c.
+    fn build_layout_context(&self) -> LayoutContext {
+        let image_cache = self.local_image_cache;
+        let font_ctx = self.font_ctx;
+        let screen_size = self.screen_size.unwrap();
+        let doc_url = self.doc_url.clone();
+
+        LayoutContext {
+            image_cache: image_cache,
+            font_ctx: font_ctx,
+            doc_url: doc_url.unwrap(),
+            screen_size: Rect(Point2D(Au(0), Au(0)), screen_size),
+        }
+    }
+
     fn handle_request(&mut self) -> bool {
         match self.from_script.recv() {
             AddStylesheetMsg(sheet) => self.handle_add_stylesheet(sheet),
@@ -147,20 +170,16 @@ impl Layout {
         debug!("layout: damage is %?", data.damage);
         debug!("layout: parsed Node tree");
         debug!("%?", node.dump());
-
         // Reset the image cache.
         self.local_image_cache.next_round(self.make_on_image_available_cb(script_chan));
 
+        self.doc_url = Some(doc_url);
         let screen_size = Size2D(Au::from_px(data.window_size.width as int),
                                  Au::from_px(data.window_size.height as int));
+        self.screen_size = Some(screen_size);
 
         // Create a layout context for use throughout the following passes.
-        let mut layout_ctx = LayoutContext {
-            image_cache: self.local_image_cache,
-            font_ctx: self.font_ctx,
-            doc_url: doc_url,
-            screen_size: Rect(Point2D(Au(0), Au(0)), screen_size)
-        };
+        let mut layout_ctx = self.build_layout_context();
 
         // Initialize layout data for each node.
         //
@@ -292,6 +311,55 @@ impl Layout {
 
                 reply_chan.send(response)
             }
+            HitTestQuery(node, point) => {
+                // FIXME: Isolate this transmutation into a single "bridge" module.
+                let node: AbstractNode<LayoutView> = unsafe {
+                    transmute(node)
+                };
+                let mut flow_node: AbstractNode<LayoutView> = node;
+                for node.traverse_preorder |node| {
+                    if node.layout_data().flow.is_some() {
+                        flow_node = node;
+                        break;
+                    }
+                };
+
+                let response = match flow_node.layout_data().flow {
+                    None => {
+                        debug!("HitTestQuery: flow is None");
+                        Err(())
+                    }
+                    Some(flow) => {
+                        let layout_ctx = self.build_layout_context();
+                        let builder = DisplayListBuilder {
+                            ctx: &layout_ctx,
+                        };
+                        let display_list: @Cell<DisplayList<RenderBox>> =
+                            @Cell(DisplayList::new());
+                        flow.build_display_list(&builder,
+                                                &flow.position(),
+                                                display_list);
+                        // iterate in reverse to ensure we have the most recently painted render box
+                        let (x, y) = (Au::from_frac_px(point.x as float),
+                                      Au::from_frac_px(point.y as float));
+                        let mut resp = Err(());
+                        let display_list = &display_list.take().list;
+                        for display_list.each_reverse |display_item| {
+                            let bounds = display_item.bounds();
+                            if x <= bounds.origin.x + bounds.size.width &&
+                               bounds.origin.x <= x &&
+                               y < bounds.origin.y + bounds.size.height &&
+                               bounds.origin.y <  y {
+                                resp = Ok(HitTestResponse(display_item.base().extra.node()));
+                                break;
+                            }
+                        }
+                        resp
+                    }
+                };
+
+                reply_chan.send(response)
+            }
         }
     }
 
diff --git a/src/components/main/platform/common/glut_windowing.rs b/src/components/main/platform/common/glut_windowing.rs
index 8df2985425b..613064f2110 100644
--- a/src/components/main/platform/common/glut_windowing.rs
+++ b/src/components/main/platform/common/glut_windowing.rs
@@ -7,8 +7,8 @@
 /// GLUT is a very old and bare-bones toolkit. However, it has good cross-platform support, at
 /// least on desktops. It is designed for testing Servo without the need of a UI.
 
-use windowing::{ApplicationMethods, CompositeCallback, LoadUrlCallback, ResizeCallback};
-use windowing::{ScrollCallback, WindowMethods};
+use windowing::{ApplicationMethods, CompositeCallback, LoadUrlCallback, ClickCallback};
+use windowing::{ResizeCallback, ScrollCallback, WindowMethods};
 
 use alert::{Alert, AlertMethods};
 use core::libc::c_int;
@@ -35,6 +35,7 @@ pub struct Window {
     composite_callback: Option<CompositeCallback>,
     resize_callback: Option<ResizeCallback>,
     load_url_callback: Option<LoadUrlCallback>,
+    click_callback: Option<ClickCallback>,
     scroll_callback: Option<ScrollCallback>,
 
     drag_origin: Point2D<c_int>,
@@ -54,6 +55,7 @@ impl WindowMethods<Application> for Window {
             composite_callback: None,
             resize_callback: None,
             load_url_callback: None,
+            click_callback: None,
             scroll_callback: None,
 
             drag_origin: Point2D(0, 0),
@@ -77,6 +79,7 @@ impl WindowMethods<Application> for Window {
             window.handle_key(key)
         }
         do glut::mouse_func |_, _, x, y| {
+            window.handle_click(x, y);
             window.start_drag(x, y)
         }
         do glut::motion_func |x, y| {
@@ -111,6 +114,11 @@ impl WindowMethods<Application> for Window {
         self.load_url_callback = Some(new_load_url_callback)
     }
 
+    /// Registers a callback to be run when a click event occurs.
+    pub fn set_click_callback(&mut self, new_click_callback: ClickCallback) {
+        self.click_callback = Some(new_click_callback)
+    }
+
     /// Registers a callback to be run when the user scrolls.
     pub fn set_scroll_callback(&mut self, new_scroll_callback: ScrollCallback) {
         self.scroll_callback = Some(new_scroll_callback)
@@ -136,6 +144,14 @@ impl Window {
         }
     }
 
+    /// Helper function to handle a click
+    fn handle_click(&self, x: c_int, y: c_int) {
+        match self.click_callback {
+            None => {}
+            Some(callback) => callback(Point2D(x as f32, y as f32)),
+        }
+    }
+
     /// Helper function to start a drag.
     fn start_drag(&mut self, x: c_int, y: c_int) {
         self.drag_origin = Point2D(x, y)
diff --git a/src/components/main/windowing.rs b/src/components/main/windowing.rs
index 708ea4105ec..9a9cefaf03b 100644
--- a/src/components/main/windowing.rs
+++ b/src/components/main/windowing.rs
@@ -16,6 +16,10 @@ pub type ResizeCallback = @fn(uint, uint);
 /// Type of the function that is called when a new URL is to be loaded.
 pub type LoadUrlCallback = @fn(&str);
 
+/// Type of the function that is called when hit testing is to be performed.
+/// FIXME this currently does not discriminate between left and right clicks or any modifiers
+pub type ClickCallback = @fn(Point2D<f32>);
+
 /// Type of the function that is called when the user scrolls.
 pub type ScrollCallback = @fn(Point2D<f32>);
 
@@ -38,6 +42,8 @@ pub trait WindowMethods<A> {
     pub fn set_resize_callback(&mut self, new_resize_callback: ResizeCallback);
     /// Registers a callback to run when a new URL is to be loaded.
     pub fn set_load_url_callback(&mut self, new_load_url_callback: LoadUrlCallback);
+    /// Registers a callback to run when the user clicks.
+    pub fn set_click_callback(&mut self, new_click_callback: ClickCallback);
     /// Registers a callback to run when the user scrolls.
     pub fn set_scroll_callback(&mut self, new_scroll_callback: ScrollCallback);
 
diff --git a/src/components/script/dom/event.rs b/src/components/script/dom/event.rs
index 7b1fba2ac37..a0ef39d8fca 100644
--- a/src/components/script/dom/event.rs
+++ b/src/components/script/dom/event.rs
@@ -7,9 +7,12 @@ use dom::window::Window;
 use dom::bindings::codegen::EventBinding;
 use dom::bindings::utils::{DOMString, ErrorResult, WrapperCache};
 
+use geom::point::Point2D;
+
 pub enum Event {
     ResizeEvent(uint, uint, comm::Chan<()>),
-    ReflowEvent        
+    ReflowEvent,
+    ClickEvent(Point2D<f32>),
 }
 
 pub struct Event_ {
diff --git a/src/components/script/layout_interface.rs b/src/components/script/layout_interface.rs
index b442dc440d3..86077244ecd 100644
--- a/src/components/script/layout_interface.rs
+++ b/src/components/script/layout_interface.rs
@@ -6,12 +6,13 @@
 /// coupling between these two components, and enables the DOM to be placed in a separate crate
 /// from layout.
 
-use dom::node::{AbstractNode, ScriptView};
+use dom::node::{AbstractNode, ScriptView, LayoutView};
 use script_task::ScriptMsg;
 
 use core::comm::{Chan, SharedChan};
 use geom::rect::Rect;
 use geom::size::Size2D;
+use geom::point::Point2D;
 use gfx::geometry::Au;
 use newcss::stylesheet::Stylesheet;
 use std::net::url::Url;
@@ -43,6 +44,8 @@ pub enum LayoutQuery {
     ContentBoxQuery(AbstractNode<ScriptView>),
     /// Requests the dimensions of all the content boxes, as in the `getClientRects()` call.
     ContentBoxesQuery(AbstractNode<ScriptView>),
+    /// Requests the node containing the point of interest
+    HitTestQuery(AbstractNode<ScriptView>, Point2D<f32>),
 }
 
 /// The reply of a synchronous message from script to layout.
@@ -54,6 +57,8 @@ pub enum LayoutResponse {
     ContentBoxResponse(Rect<Au>),
     /// A response to the `ContentBoxesQuery` message.
     ContentBoxesResponse(~[Rect<Au>]),
+    /// A response to the `HitTestQuery` message.
+    HitTestResponse(AbstractNode<LayoutView>),
 }
 
 /// Dirty bits for layout.
diff --git a/src/components/script/script_task.rs b/src/components/script/script_task.rs
index cf99428c677..094336bf1ab 100644
--- a/src/components/script/script_task.rs
+++ b/src/components/script/script_task.rs
@@ -7,11 +7,11 @@
 
 use dom::bindings::utils::GlobalStaticData;
 use dom::document::Document;
-use dom::event::{Event, ResizeEvent, ReflowEvent};
+use dom::event::{Event, ResizeEvent, ReflowEvent, ClickEvent};
 use dom::node::define_bindings;
 use dom::window::Window;
-use layout_interface::{AddStylesheetMsg, BuildData, BuildMsg, Damage, LayoutQuery};
-use layout_interface::{LayoutResponse, LayoutTask, MatchSelectorsDamage, NoDamage};
+use layout_interface::{AddStylesheetMsg, BuildData, BuildMsg, Damage, LayoutQuery, HitTestQuery};
+use layout_interface::{LayoutResponse, HitTestResponse, LayoutTask, MatchSelectorsDamage, NoDamage};
 use layout_interface::{QueryMsg, ReflowDamage};
 use layout_interface;
 
@@ -460,6 +460,23 @@ impl ScriptContext {
                     self.relayout()
                 }
             }
+
+            ClickEvent(point) => {
+                debug!("ClickEvent: clicked at %?", point);
+                let root = match self.root_frame {
+                    Some(ref frame) => frame.document.root,
+                    None => fail!("root frame is None")
+                };
+                match self.query_layout(HitTestQuery(root, point)) {
+                    Ok(node) => match node {
+                        HitTestResponse(node) => debug!("clicked on %?", node.debug_str()),
+                        _ => fail!(~"unexpected layout reply")
+                    },
+                    Err(()) => {
+                        println(fmt!("layout query error"));
+                    }
+                };
+            }
         }
     }
 }